Buildings collapsed, power lines were downed and roads buckled as the quake hit just outside the city of Christchurch at around 4.30am local time (5.30pm Irish time).

Speaking to the Irish Independent last night, John Thornton, who is originally from Dundrum in Dublin, told how he was awoken by the violent shaking and he and his New Zealand wife Cathy rushed to their two children, Jake (8) and Kayligh (6).

"I woke up because I thought I heard the noise of a train and then I realised it was an earthquake. We're only about 30km away from the epicentre and the whole house started rocking backwards and forwards.

"My first thought was the kids but when I got up I was thrown against a wall. We managed to get to the kids and the four of us just sheltered under a table. It lasted no more than a minute but it was very violent . . . It's probably the longest minute of your life when you're being thrown about," he added.

Mr Thornton immediately contacted his family back home in Ireland to reassure them that he, his wife and the children were uninjured.

The area experienced sporadic aftershocks, but none as strong as the main quake.

The family live in the town of Kaiapoi on the outskirts of Christchurch. Mr Thornton said that while his house appeared to have sustained no structural damage, the bridge leading out of the town was impassable. "Seemingly there is quite a lot of damage in and around the centre of Christchurch. Quite a few facades of buildings have fallen down and there's some looting going on.

"We have no power and no water and it's likely we won't have it for a couple of hours yet," he added.

Mr Thornton, who works as a carpenter, emigrated with his family in 2005 and this was the first major quake they have experienced. "We've had a few little rattles before, but I certainly noticed this one," he said.

The Department of Foreign Affairs said last night that it had received no reports of any Irish injuries in the region. The quake, which hit Sheffield, some 19 miles (30km) west of the southern city of Christchurch, shook a wide area with some residents there saying buildings had collapsed and power was severed.

Christchurch police reported some road damage in parts of the city of 400,000 people, with a series of sharp aftershocks rocking the area. Police officers cordoned off some streets where rubble was strewn about from the quake. One Christchurch resident, Colleen Simpson, said panicked residents ran into the street in their pyjamas.